#include <iostream>
using namespace std;
namespace wd{
int number=10;
void display(){
    std::cout<<"wd::display"<<std::endl;
}
}
void test0(){
    std::cout<<"wd::number="<<wd::number<<endl;
    wd::display();
}
int main(int argc, char * argv[]){
    test0();
    return 0;
}

